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Data Access
Virtual Magnetospheric Observatory
Characteristics of Reconnection Sites and Fast Flow Channels in an MHD Simulation. Supplementary MHD simulation movie mS4-BIF.mp4 for 14 March 2008.
var authors='R.L. McPherron; M. El-Alaoui; R.J. Walker; and R.L. Richard';
document.write(authors);
(2020).
Characteristics of Reconnection Sites and Fast Flow Channels in an MHD Simulation. Supplementary MHD simulation movie mS4-BIF.mp4 for 14 March 2008..
[Data set].
University of California, Los Angeles.
https://doi.org/10.21978/p8rw5g. Accessed on document.write(currentDateStr);.
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ResourceID
spase://NASA/DisplayData/UCLA/Global-MHD-code/mS4-BIF/PT10S
Description
Section 4.1 of the text describes our procedure for identifying the locations of x-lines in a map of the neutral surface.
At each value of Y in an interpolated grid, we scan the entire length of the trace of Vx from -10 to -70 Re. A function finds all
intervals of Vx>=250 km/s and Vx less then or equal to -250 km/s. We call these earthward and tailward fast flow intervals. We define
a bifurcation of fast flow as the point at which Vx changes sign from fast earthward to fast tailward flow. In simple cases, this
transition occurs in about 2 Re (20 grid points). The zero crossing is the location of the x-line at this value of Y. As described
in the text, we process the arrays of zero crossings to define a line in the neutral surface. We display this information as lines
parallel to X at fixed Y. Intervals of fast earthward flow are represented by a thick red line. Fast flow is a thick blue line. The
zero crossing is a gray circle. After completion of the plot, we add x-lines as colored ropes (yellow with black stripes). Each map is
in a file and subsequently made into a movie. The movie illustrates the formation and evolution of x-lines.
The movie begins at 04:00 UT with at least five significant x-lines and six earthward flow channels. This is the start of the growth
phase of a substorm. As time advances the locations of the x-lines change as flow channels move away from them. New lines form and
channels merge. When the movie approaches substorm onset at 04:44 UT the x-lines merge into a single long x-line stretching diagonally
across the tail. About 04:35, the nose of the fast earthward flow channel penetrates close to the Earth, and then begins to sweep
westward to earlier local times. At this, time the movie mS02 and the text Figure 13 shows magnetic flux accumulating close to the Earth.
At 04:50 UT, the single channels spawns new channels that flow directly toward Earth rather than along the diagonal channel.
Metadata Rights
CC0-1.0:
Creative Commons Zero v1.0 Universal
Note
CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions. The actual data/software may be subject to a different license.
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Details
Version:2.7.1
DisplayData
ResourceID
spase://NASA/DisplayData/UCLA/Global-MHD-code/mS4-BIF/PT10S
NamingAuthority
NASA
ResourceType
DisplayData
ResourceHeader
ResourceName
Characteristics of Reconnection Sites and Fast Flow Channels in an MHD Simulation. Supplementary MHD simulation movie mS4-BIF.mp4 for 14 March 2008.
DOI
https://doi.org/10.21978/p8rw5g
ReleaseDate
2026-06-26 15:10:58Z
RevisionHistory
RevisionEvent
ReleaseDate
2022-03-16 00:00:00Z
Note
Only known prior ReleaseDate of the metadata
RevisionEvent
ReleaseDate
2025-03-03 13:30:47Z
Note
Modified Funding AwardNumber. ZCB
RevisionEvent
ReleaseDate
2025-09-30 14:25:28Z
Note
Updated PublishedBy name to match ROR Registry. Added ResourceType and NamingAuthority. ZCB
RevisionEvent
ReleaseDate
2025-12-04 13:28:08Z
Note
Added MetadataRightsList. Updated to 2.7.1. ZCB
RevisionEvent
ReleaseDate
2026-06-26 15:10:58Z
Note
Add 'Z' to TemporalDescription:TimeSpan:StartDate, TemporalDescription:TimeSpan:StopDate. ZCB
Description
Section 4.1 of the text describes our procedure for identifying the locations of x-lines in a map of the neutral surface.
At each value of Y in an interpolated grid, we scan the entire length of the trace of Vx from -10 to -70 Re. A function finds all
intervals of Vx>=250 km/s and Vx less then or equal to -250 km/s. We call these earthward and tailward fast flow intervals. We define
a bifurcation of fast flow as the point at which Vx changes sign from fast earthward to fast tailward flow. In simple cases, this
transition occurs in about 2 Re (20 grid points). The zero crossing is the location of the x-line at this value of Y. As described
in the text, we process the arrays of zero crossings to define a line in the neutral surface. We display this information as lines
parallel to X at fixed Y. Intervals of fast earthward flow are represented by a thick red line. Fast flow is a thick blue line. The
zero crossing is a gray circle. After completion of the plot, we add x-lines as colored ropes (yellow with black stripes). Each map is
in a file and subsequently made into a movie. The movie illustrates the formation and evolution of x-lines.
The movie begins at 04:00 UT with at least five significant x-lines and six earthward flow channels. This is the start of the growth
phase of a substorm. As time advances the locations of the x-lines change as flow channels move away from them. New lines form and
channels merge. When the movie approaches substorm onset at 04:44 UT the x-lines merge into a single long x-line stretching diagonally
across the tail. About 04:35, the nose of the fast earthward flow channel penetrates close to the Earth, and then begins to sweep
westward to earlier local times. At this, time the movie mS02 and the text Figure 13 shows magnetic flux accumulating close to the Earth.
At 04:50 UT, the single channels spawns new channels that flow directly toward Earth rather than along the diagonal channel.
Acknowledgement
Mostafa El-Alaoui, Raymond J. Walker; Robert L. McPherron
PublicationInfo
Authors
R.L. McPherron; M. El-Alaoui; R.J. Walker; and R.L. Richard
PublicationDate
2020-08-31 00:00:00Z
PublishedBy
University of California, Los Angeles
Funding
Agency
NASA
Project
Substorm current wedge development and evolution using THEMIS observation and simulations
AwardNumber
NNX17AB83G
Funding
Agency
NASA
Project
Structure and evolution of plasma sheet fast flows using THEMIS observation and global MHD simulations
AwardNumber
NNX15AI63G
Funding
Agency
NSF
Project
GEM: A Statistical Study of the Substorm Sequence and Phenomena Associated with Expansion Onset
AwardNumber
1602588
Contacts
Role
Person
StartDate
StopDate
Note
1.
GeneralContact
spase://SMWG/Person/Robert.L.McPherron
2.
MetadataContact
spase://SMWG/Person/James.M.Weygand
InformationURL
Name
Virtual Magnetospheric Observatory directory containing movies for Journal of Gephysical Research publication.
URL
http://vmo.igpp.ucla.edu/data1/McPherron/Simulation_Movies_and_Data/Simulation_Movies/mS2-Bz.avi
Description
Supplimentary movies for JGR publication
AccessInformation
RepositoryID
spase://SMWG/Repository/UCLA/VMO
Availability
Online
AccessRights
Open
AccessURL
Name
Virtual Magnetospheric Observatory
URL
http://vmo.igpp.ucla.edu/data1/
Description
Virtual Magnetospheric Observatory
Language
EN
Format
AVI
Acknowledgement
If data downloaded from the VMO Data Repository are used in publication kindly acknowledge the Virtual Magnetospheric Observatory, Earth, Planetary and Space Science Department, University of California, Los Angeles for providing access to the data.
ProcessingLevel
Raw
ProviderName
UCLA M. El-Alaoui MHD Simulation
ProviderResourceName
MHD Simulation Movies
ProviderProcessingLevel
Raw
InstrumentIDs
spase://SMWG/Instrument/UCLA/Global-MHD-code
MeasurementType
ThermalPlasma
TemporalDescription
TimeSpan
StartDate
2008-03-14 04:00:00Z
StopDate
2008-03-14 05:00:00Z
DisplayCadence
PT10S
ObservedRegion
Earth.Magnetosphere
Keywords
MHD Simulation
Substorm
High Speed Earthward Flows
Parameter #1
Name
MHD simulation movie of GSM X component of position for 14 March 2008
ParameterKey
X component of position
Description
Two dimensional display of this movie of the GSM X component of position is on the original.
Cadence
PT10S
Units
Re
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
3840 1890
Description
Each image is 3840 pixels by 1890 pixels and there are 360 frames in the movie.
ValidMin
-70
ValidMax
0
Support
Qualifier
Direction
SupportQuantity
Positional
Parameter #2
Name
MHD simulation movie of GSM Y component of position for 14 March 2008
ParameterKey
Y component of position
Description
Two dimensional display of this movie of the GSM Y component of position is on the original.
Cadence
PT10S
Units
Re
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
3840 1890
Description
Each image is 3840 pixels by 1890 pixels and there are 360 frames in the movie.
ValidMin
-20
ValidMax
20
Support
Qualifier
Direction
SupportQuantity
Positional
Parameter #3
Name
MHD simulation movie of GSM X component of plasma flow velocity for 14 March 2008
ParameterKey
Vx component of plasma flow
Description
Two dimensional display of this movie of the GSM X component of plasma flow velocity is on the original, not interpolated grid. Red means Vx flows earthward and is greater then or equal to 250 km/s, Blue means Vx flows tailward and is less then or equal to 250 km/s, and white means flows are between -250 and 250 km/s.
Cadence
PT10S
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
3840 1890
Description
Each image is 3840 pixels by 1890 pixels and there are 360 frames in the movie.
ValidMin
-250
ValidMax
250
Support
Qualifier
Vector
SupportQuantity
Velocity
Parameter #4
Name
MHD simulation movie of GSM plasma flow velocity for 14 March 2008
ParameterKey
Vx and Vy components of plasma flow
Description
Two dimensional display of this movie of the GSM plasma flow velocity interpolated grid.
Cadence
PT10S
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
3840 1890
Description
Each image is 3840 pixels by 1890 pixels and there are 360 frames in the movie.
ValidMin
-300
ValidMax
300
Support
Qualifier
Vector
SupportQuantity
Velocity